A midfielder, his career began with Mansfield Town in 1995, where he spent the first six years of his career, making 160 league appearances. In 2001, he transferred to Hartlepool United, where he spent another six years, racking up 127 appearances in the league. He was sent out on loan to Stockport County, Port Vale, and Rochdale in the final years of his spell. In 2007, he left the professional game to sign for Salisbury City, before taking up the management position at the club in 2010. He led the club to promotion into the Conference Premier from the Southern League with two play-off final victories in three seasons.
He was appointed manager of Bristol Rovers in March 2014, but could not prevent the club from dropping out of the Football League. However, one year later, Clarke successfully guided Bristol Rovers back into the Football League after winning the 2015 Conference Premier play-off Final, and then went on to take the club into League One with promotion out of League Two in 2015–16.
Born in Mansfield, Nottinghamshire, Clarke started his career at Mansfield Town when he joined their youth set up at the age of just 10. He made his way through the ranks and was offered a professional contract at Field Mill by Andy King in 1995. The "Stags" struggled near the foot of the Third Division in 1995–96, rising to mid-table in 1996–97 and 1997–98, before finishing one place outside the play-offs in 1998–99. They then dropped back into the lower half of the table in 1999–2000 and 2000–01 after manager Steve Parkin was replaced by Bill Dearden. While at Mansfield he became a fan favourite, partly because he was a home grown talent. He made over 150 league and cup appearances for the club, scoring 27 goals. As his contract ran to its end, he attracted the attention of several other clubs and he was offered a contract at Hartlepool United by Chris Turner.
Clarke signed for Hartlepool in July 2001 on a free transfer, courtesy of the Bosman ruling, but Hartlepool still had to pay £80,000 as he was under 24. He was seen by many as the replacement for Tommy Miller. Clarke originally failed to cement his place in the starting 11 and found himself in and out of the team, making 26 league starts and 9 substitute appearances. However, he still managed to score 7 league goals, including a hat-trick in a 7–1 win over Swansea City.
The following season was much more successful for Clarke as he played in nearly all of Hartlepool's matches and added another seven goals to his tally in Hartlepool's promotion winning campaign. The arrival of manager Neale Cooper saw Clarke's opportunities in the first team in 2003–04 limited, as Eifion Williams was preferred on the right wing. Clarke only started 23 league matches, but he still managed to make a further 12 substitute appearances.
In the 2004–05 season, Clarke suffered a knee injury that prevented him from taking part in any of Hartlepool's league games. However, he did make an appearance for Stockport County during a loan spell, but this was cut short as Clarke picked up another knee problem. In September 2005 Clarke was loaned to Port Vale, again just playing the one game. His appearances were again limited once he returned to Victoria Park. In July 2006 he was loaned to Rochdale, where he made 12 appearances. He was released by 'Pool in May 2007.
On 3 July 2007 he signed for newly promoted Conference National club Salisbury City. He was strongly influenced by former team mate Tommy Widdrington to make the switch South, and was the third signing made by Nick Holmes. He helped the club avoid relegation in the 2008–09 season, which was a good achievement for the club.
At the beginning of the 2009–10 season he became Salisbury's most senior player and was duly given the captain's armband by Widdrington, who had recently been appointed manager. He captained the club to a mid-table finish, however Salisbury were demoted down into the Southern League Premier Division as punishment for their severe financial problems.
In July 2010, Tommy Widdrington left Salisbury City for the job of assistant manager at Southend United. As a result of this, Clarke became joint caretaker manager beside Mikey Harris. The next month he was made player-manager on a permanent basis, with Harris as his assistant. After his first season, the 'Whites' won promotion from the Southern League Premier Division via the play-offs, winning 3–2 on penalties after a 2–2 draw with Hednesford Town.
Clarke led Salisbury to the Second Round of the FA Trophy in his second season in charge. He also made history when his side beat Grimsby Town in the FA Cup Second Round, taking Salisbury to the Third Round of the FA Cup for the first time in the club's history, where they faced Sheffield United at Bramall Lane. At the start of the campaign he had stated his intention to sign promising young players, and during the January transfer window he signed 19-year-old Matt Clark and former England youth player Abdulai Bell-Baggie, as well as 29-year-old striker Robbie Matthews. However, he also placed winger Charlie Knight on the transfer list along with striker Jake Reid, defender Josh Casey, and winger Adam Kelly. They finished the 2011–12 campaign comfortably in tenth place, and Clarke extended his contract at the club to another season.
Clarke's pre-season signings for 2012–13 included Jamie White from Winchester City, James Clarke from Oxford City, and Theo Lewis after his release from Cheltenham Town. These signings proved successful, and helped to take Salisbury into second place in the Conference South by April. The team's success saw him strongly linked with the vacant management position at Hartlepool United in October 2012, though he ultimately remained at Salisbury. The club finished four points behind champions Welling United, and had to make do with a play-off place. Promotion was secured with a 3–2 extra-time victory over Dover Athletic in the play-off final.
In June 2013, Clarke was appointed as assistant manager of League Two club Bristol Rovers, supporting John Ward. Following another season of struggle at Rovers, Ward was moved to a role as Director of football and was replaced as manager by Clarke in March 2014. His first game on 29 March ended with a 1–0 victory over Morecambe at the Memorial Stadium, and Clarke said that "I tried to get my philosophy across today and I think we did it in spells and we need to more of that". Rovers were relegated out of the Football League on the final day of the 2013–14 after a 1–0 defeat to Mansfield Town; a draw would have been enough to keep the club up, as they were relegated on goal difference.
He oversaw a rapid turnover of players for the 2014–15 season, releasing 16 players and signing 13 players on free transfers, including striker Matty Taylor. After a poor start Rovers rose up the table and ended the campaign in second place, one point behind Barnet. Clarke led Rovers to promotion with a 5–3 penalty shoot-out victory over Grimsby Town at Wembley Stadium in the 2015 Conference Premier play-off Final on 17 May 2015, after a 1–1 draw after extra time. He won three Manager of the Month awards during the season, in September, December and February.
Rovers achieved a second successive promotion with a third-place finish in the 2015–16 campaign. Clarke was named as Manager of the Month for March after winning six of seven games by "playing exciting and attacking football" according to head judge George Burley. Promotion was achieved on the final day of the season with a stoppage-time winner against Dagenham & Redbridge, which took them above Accrington Stanley into third-place. On 27 May 2016, Clarke turned down the opportunity to manage Championship club Leeds United and signed a new three-year contract with Bristol Rovers.
Darrell celebrated his 1000th day in charge of Rovers on 21 December 2016 with Rovers sitting 12th in the league heading into the Christmas period. During late March 2017, with his club sitting just outside the League One play off places, Norwich City were reported to be interested in Clarke following the sacking of previous manager Alex Neil. Whilst Clarke never turned down any potential offer he instead pledged his loyalty to Rovers instead, the announcement coming a day after his three year anniversary of his first Rovers match in charge. Rovers finished in 10th-place in 2016–17.
In June 2017, Clarke signed a new five-year contract.As of match played 19 September 2017
Hartlepool UnitedThird Division runner-up: 2002–03
Salisbury CitySouthern League Premier Division play-offs: 2010–11
Conference South play-offs: 2012–13
IndividualConference Premier Manager of the Month: September 2014, December 2014, February 2015
League Two Manager of the Month: March 2016
Bristol RoversConference Premier play-offs: 2014–15
League Two third-place promotion: 2015–16